Particle Ratios as a Probe of the QCD Critical Temperature

Understand

We show how the measured particle ratios can be used to provide non-trivial information about the critical temperature of the QCD phase transition.

• This is obtained by including the effects of highly massive Hagedorn resonances on statistical models, which are used to describe hadronic yields.
• The inclusion of Hagedorn states creates a dependence of the thermal fits on the Hagedorn temperature, $T_H$, which is assumed to be equal to $T_c$, and leads to an overall improvement of thermal fits.
• We find that for Au+Au collisions at RHIC at $\sqrt{s_{NN}}=200$ GeV the best square fit measure, $\chi^2$, occurs at $T_c \sim 176$ MeV and produces a chemical freeze-out temperature of 172.6 MeV and a baryon chemical potential of 39.7 MeV.